Transport at the LaAlO3 /SrTiO3 interface

Conventional semiconductor two-dimensional electron systems (2DESs) have long been important for fundamental physics and modern technology. Thus, the 2004 discovery of a conducting interface between the insulators LaAlO3 and transition-metal oxide SrTiO3 fuelled intense research on this novel 2DES having strong electronic correlations. Indeed, subsequent reports on ferromagnetism and superconductivity in this oxide 2DES highlight its uniqueness compared to semiconductors. However, its origin and electronic composition are still largely open questions. In this talk, I will show experimental evidence for a multicarrier composition at the oxide interface, deduced from our perpendicular field magnetotransport data. This observation has a surprising consequence for 2D superconductivity in this system. Even more surprising, is the effect of an in-plane magnetic field on the magnetoresistance. I will conclude by presenting very recent data suggesting “spontaneous” ordering in the 2DES induced by the in-plane magnetic field.